This application is a division of U.S. patent application No. 09/704,182, filed Nov. 1, 2000, which issued on Jul. 29, 2003 as U.S. Pat. No. 6,598,633; which claims the benefit of U.S. Provisional Patent Application No. 60/186,463, filed Mar. 2, 2000.
The present invention concerns vehicle tire safety supports that are mounted inside the tires, on their rims, in order to carry the weight in case of tire failure. In particular, it concerns the connection between those safety supports and the rims on which they are mounted.
The main function of the safety supports is to carry the weight in case of severe loss of inflation pressure of the tire. When tires are inflated normally, the safety supports should interfere with the dynamic properties of the tires as little as possible. In particular, they should remain well centered around the rim in order to avoid any unbalance effect, whatever the temperature of the support and the traveling speed of the vehicle. They should also be capable of being mounted on the rims of vehicle wheels and demounted easily.
U.S. Pat. No. 5,690,762 relates to a safety support made of an elastic material designed to be mounted on a well-base rim of an ordinary passenger vehicle. This support contains a body and a base designed to come in contact with the rim. The support further includes annular reinforcements circumferentially oriented and appreciably inextensible, the radius of which is slightly greater than the radius of the flange of the rim for which the support is provided. The base consists of two annular zones, whose inner radius in free state is less than that of the part of the rim on which they must bear; the compression of these annular zones therefore ensures good centering of the support on the rim. The function of the annular reinforcements is, notably, to prevent the annular zones from stretching, by reason of high-speed centrifugal forces, until losing contact with the rim.
When a safety support is designed to equip a rim in two parts or a rim possessing a bearing for a support, the radius of which is greater than that of one of the rim flanges, as shown in FIG. 1, the safety support is mounted by insertion of the support on the corresponding rim bearing. One can refer to U.S. Pat. No. 5,836,366 which describes a method of mounting an assembly made up of a tire and tread support on such a wheel rim bearing. It is important for the support to be well centered on the rim bearing while maintaining easy mounting and demounting, as well as satisfactory endurance.
On the other hand, when annular reinforcements are necessary to withstand centrifugal forces, the annular reinforcements can be placed in the base. This is the case with the support disclosed by application EP 0,796,747 A1. Such a position of the annular reinforcements facilitates the manufacture of the support.
For such a support, taking into account the manufacturing tolerances of the rim and support, it is no longer possible to use radially inner annular zones, the compression of which ensures good centering on the rim, whatever the speed, while ensuring easy mounting and demounting.
“Equatorial plane” of a safety support is understood to be any plane perpendicular to the axis of rotation of the support and “mid-equatorial plane” is understood to be the equatorial plane placed in the middle of the support.
The “axial plane” of a support or wheel is understood to be any plane passing through the axis of rotation of the support or wheel.